KDE doesn’t render many of the nerd-font glyphs

[haizaar]

Describe the bug

I’m on NixOS 23.05 and found a strange issue where KDE (QT?) based apps don’t display many nerd-font glyphs properly, e.g. those suggested in the starship manual. It’s only in KDE/QT apps, and only on NixOS (KDE Neon / Kubuntu work fine)

The font I use is “MesloLGSDS Newd Front Mono”

Chrome displays them just fine as you can see below (at least I do)

💨🕙💦🦬🍞✨🦕🐋🔮🇬️🌱

GTK-based app have no issues as well. Here is tilix terminal for example:

But KDE/QT based stuff struggles. Here is how I see it in the konsole (Note the rectangles instead of glyphs)

I looks like NixOS-specific issue because it all works just fine in KDE-neon running in Virtualbox (KDE 5.27 on Wayland):

Same issue happens with kate as well as any QT app (Dolphin, klipper, etc.)

All I do in confugration.nix is

services.xserver.displayManager.defaultSession = "plasmawayland";
services.xserver.desktopManager.plasma5.enable = true;

Notify maintainers

CC @ttuegel @nyanloutre

Metadata

Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

[user@system:~]$ nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 6.1.37, NixOS, 23.05 (Stoat), 23.05.1622.c99004f75fd`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.13.3`
 - channels(root): `"home-manager-23.05.tar.gz, nixos-23.05"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/kde-doesnt-render-nerd-font-glyphs/30153/2

[haizaar]

Fixed by applying font configuration as mentioned here: https://github.com/NixOS/nixpkgs/issues/86601#issuecomment-757959059. Though I understand the concerns why it's not the default, that was a hard one to dig out.